LAUSR

Abstract The sulfated zirconia was prepared by directly impregnating ammonium persulphate on the crystalline zirconia and followed by the calcination temperatures of 300–500°C. The structural properties of the catalysts were characterized by X-ray diffraction (XRD), N 2 adsorption-desorption, ammonia temperature programmed desorption (NH 3 -TPD), Fourier transform infrared spectroscopy (FT-IR) and a scanning electron microscope (SEM) equipped with an energy dispersive spectroscope (EDS). The experiment results demonstrated that the catalysts presented the tetragonal structure of zirconia and high crystallinity. The catalyst calcined at 500°C possessed the highest sulfur content and acidic sites in the catalysts. The catalyst exhibited high catalytic activity in transesterification of soybean oil with methanol. The yield of biodiesel achieved 84.6% because of the preferable super-acid sites on the surface of the catalyst.